1. Field
The following description relates to an apparatus and method for frame synchronization in a satellite communication system, and more particularly, to an apparatus and method in which a receiver synchronizes frames of signals transmitted through satellites.
2. Description of the Related Art
Satellite communication systems, specifically, DVB-S2 (Digital Video Broadcasting via Satellite, Second Generation) has achieved extension of satellite channel capacity up to 100 to 200% by using Adaptive Coding and Modulation (ACM) of selecting an optimal modulation scheme and an optimal coding rate adaptively to the state of a satellite communication channel. Introduction of a channel coding technique such as Low Density Parity Check (LDPC) has implemented a transmission system that satisfies a low bit error rate even under a unstable environment such as at a low Signal-to-Noise Rate (SNR). According to a burst-based satellite communication mode, a transmitter of a satellite communication system transmits each frame after appending a short preamble at a start point from which a burst is transmitted. Also, a receiver of the satellite communication system performs frame synchronization, symbol timing synchronization, frequency/phase synchronization, demodulation/decoding, etc., in unit of a burst, using the preamble of a received frame. In the burst-based communication mode, there may be frames in which only noise exists without any signal, and frames may be received from different users for each burst. Accordingly, the power of a received signal may vary depending on frames.
For this reason, in order to restore a received satellite signal to demodulate it, frame synchronization has to be able to be performed regardless of the signal level of a burst signal. A general method for frame synchronization obtains a correlation value between a received input signal and a known signal sequence, and determines if the correlation value exceeds a threshold value to detect a frame start point. For implementing the frame synchronization method, operation of multiplying an input signal by a known signal sequence is needed, which requires many multipliers, resulting in an increase of the overhead.